bug_fix: updating the parseKernelVersion() function

[MeherRushi]

Previously, Cilium expects the kernel version to always have 3 digits.
However, the kernel is perfectly allowed to have only 2 or even only 1 digit
for the version number.
https://github.com/torvalds/linux/blob/35a4474b5c3dd4315f72bd53e87b97f128d9bb3d/Makefile#L367

This patch makes changes to the following :

• cilium/pkg/version/version_unix.go - updated the parseKernelVersion() to
  handle single as well double digit kernel versions along with the standard
  kernel versioning.
• cilium/pkg/version/version_unix_test.go - added additional test cases

Fixes: #30630

Signed-off-by: MeherRushi meherrushi2@gmail.com

Description of change

The issue #30630 address that kernel versions of single and double digit are not being parsed by cilium. I have updated the parseKernelVersion() to handle this case.

Previously the assumption was that kernel version will be something as:
4.9.17-040917-generic

I have updated it based on the following:

We are assuming the kernel version will be one of the following:
4.9.17-040917-generic or 4.9-040917-generic or 4-generic

So as observered the kernel value is N.N.N-m or N.N-m or N-m
There for we use regular expresions to extract the patch number
from the last element of the verStrs array and append "0" to 
the verStrs array in case the until its lenght is 3 as in all
cases we want to return from this function : Major.Minor.PatchNumber

@lmb @tklauser Please do review the change in code. If it is correct, I also plan on adding test cases for the same

Fixes: #30630

Updated Kernel parsing to handle single and double digit kernel version as well

[lmb]

Could you add some tests please?

[MeherRushi]

I'll look into the changes requested and update it soon, I'll also add test cases for the same.

[MeherRushi]

Hey @lmb
Thanks for the code review. I have added the test cases as requested. I also mentioned the reasoning behind my code.
Please have a look once

[lmb]

@danehans PTAL

[tklauser]

Looks like you need to run gofmt on the change:

Unformatted Go source code:
./pkg/version/version_unix.go
diff ./pkg/version/version_unix.go.orig ./pkg/version/version_unix.go
--- ./pkg/version/version_unix.go.orig
+++ ./pkg/version/version_unix.go
@@ -28,18 +28,18 @@
 
 	// So as observered the kernel value is N.N.N-m or N.N-m or N-m
 	// There for we use regular expresions to extract the patch number
-	// from the last element of the verStrs array and append "0" to 
+	// from the last element of the verStrs array and append "0" to
 	// the verStrs array in case the until its lenght is 3 as in all
 	// cases we want to return from this function : Major.Minor.PatchNumber
 
-	patch := regexp.MustCompilePOSIX(`^[0-9]+`).FindString(verStrs[len(verStrs) - 1])
+	patch := regexp.MustCompilePOSIX(`^[0-9]+`).FindString(verStrs[len(verStrs)-1])
 	if patch == "" {
-		verStrs[len(verStrs) - 1] = "0"
+		verStrs[len(verStrs)-1] = "0"
 	} else {
-		verStrs[len(verStrs) - 1] = patch
-	}
-
-	for len(verStrs) <= 3{
+		verStrs[len(verStrs)-1] = patch
+	}
+
+	for len(verStrs) <= 3 {
 		verStrs = append(verStrs, "0")
 	}

https://github.com/cilium/cilium/actions/runs/7926471252/job/21808931886?pr=30699

[MeherRushi]

Thank you for pointing it out @tklauser .
I'll do the necessary soon

[MeherRushi]

Hey @tklauser,
I have formatted the code using gofmt
Please do take a look when possible

[tklauser]

/test

[tklauser]

Thanks

[tklauser]

@MeherRushi It seems there are still some issues reported by golangci-lint: https://github.com/cilium/cilium/actions/runs/8015579723/job/21900979066?pr=30699 Could you please fix these as well?

[MeherRushi]

@MeherRushi It seems there are still some issues reported by golangci-lint: https://github.com/cilium/cilium/actions/runs/8015579723/job/21900979066?pr=30699 Could you please fix these as well?

yes will look into it
Sorry for the issues caused
will do the necessary in a while

[danehans]

@MeherRushi the linter CI job is failing due to:

  Error: pkg/version/version_unix.go:29:11: `observered` is a misspelling of `observed` (misspell)
  	// So as observered the kernel value is N.N.N-m or N.N-m or N-m
  	         ^
  Error: pkg/version/version_unix.go:30:30: `expresions` is a misspelling of `expression` (misspell)
  	// There for we use regular expresions to extract the patch number
  	                            ^
  Error: pkg/version/version_unix.go:32:45: `lenght` is a misspelling of `length` (misspell)
  	// the verStrs array in case the until its lenght is 3 as in all

The lint Make target can be used to avoid this issue in the future. See the testing docs for additional details.

[MeherRushi]

@danehans . Thanks for pointing it out.
Extremely sorry for commiting such silly mistakes. Will make the changes soon.

[MeherRushi]

@danehans I have made the requested changes. Please have a look once

[maintainer-s-little-helper]

Commit 40100ef does not match "(?m)^Signed-off-by:".

Please follow instructions provided in https://docs.cilium.io/en/stable/contributing/development/contributing_guide/#developer-s-certificate-of-origin

[danehans]

/test

[tklauser]

/test

[MeherRushi]

Thanks for the guidance and help @tklauser @lmb @danehans @optix2000